Did you ever see two sets of dots, one white in color and the other black placed near each other? Despite the fact that the dots are exactly the same size the white dots will appear larger to the human eye than the black ones. This is known as the Galileo’s illusion. It is credited to Galileo Galilei, the famous Italian scientist.

Galileo was puzzled by the appearance of the planets and how they seemed different when seen by the naked eye and through the telescope. He knew that the illusion was caused by his eyes but he was unable to explain why it happened. Galileo assumed that the illusion was caused by blur or similar optical effects.

Scientists at the State University of New York College of Optometry finally solved the puzzle of the illusion. This is what their study revealed.  The neuroscientists discovered that dark stimuli resulted in a faithful neural response, light stimuli resulted in non-linear and exaggerated response that make the stimulus look larger.

That is why the black dots seem to be the same size that they actually are while white dots appear larger. This visual illusion occurs because the way our eyes see lightness and darkness in the world is different. Interesting outcome of a long standing science project mystery!